[IshKebab]

I have no idea what you're trying to say. With PV, if you consume one additional kWh your bank balance will be 20c lower than it would otherwise have been. You can argue semantics about whether that is a "cost" all you want, but practically the end result is the same and any financial decisions about whether to consume that kWh should have an identical result to what you'd decide if you bought the energy in for the same price.

[knollimar]

they're saying you might not use the extra energy if your PV runs year round. If you continuously had a year round surplus, you wouldn't have a need to buy any energy, so the credits would be monopoly money.

[IshKebab]

But unless you're off-grid you can always use extra PV energy by selling it to the grid.

[knollimar]

The grid doesn't give you money in these locations.

They give you credits for future consumption. You can only spend this on energy. If you always have a surplus, you will just rack up large amounts of credits.

[IshKebab]

What locations? In the UK they give you actual money. You can withdraw it.